This invention relates to CNC machine tools and more particularly to a tool changer for such machines. The invention further contemplates a novel automatic tool changer operable to reduce the cycle times of machining parts requiring the use of different tools to perform various machining operations.
In many machining operations performed by conventional CNC machine tools used in the woodworking, plastic and airframe industries, multiple tasks are required to be performed, requiring the use of different tools. Initially, tool changes were performed manually, simply by having the operator interrupt the operation of the machine, change out the tool and then resume operation. Because of the time consuming aspect of manual tool changes, automatic tool changes were developed which generally have involved moving the toolhead to a tool changer positioned on or adjacent the machine or moving the tool changer to the toolhead assembly to effect the tool change. In either of such arrangements, considerable machine motion and time has been required, resulting still in undue cycle times and less than optimal productivity. It thus has been found to be desirable and therefore the principal object of this invention to provide a tool changer for a CNC machine tool in which tool changes may be performed with minimal movement and rapidly, thereby reducing cycle times and correspondingly increasing productivity.
The present invention overcomes the disadvantages of prior art automatic tool changers by providing a tool changer mountable on the toolhead assembly of a CNC machine tool generally consisting of an array of tool holders pivotally connected to the toolhead assembly and spaced apart relative to the axis of the toolhead spindle, with each of the tool holders being selectively angularly displaceable in a plane including the axis of the spindle between a retracted position and an extended position aligning the tool holder for loading or unloading a tool with respect to the spindle. Through the use of the collet on the end of the toolhead spindle, various tools may not only be loaded and unloaded unto and off of the spindle but may be transferred between the tool holder assembly mounted on the toolhead assembly and tool holders either mounted on other components of the machine or on separate equipment.